Chemical apparatus and method of lining the same



Patented Oct. 18, 1932 UNITED. STATES PATENT OFFICE RALPH I1. DUFF, OF BOSE I-LE, NEW JERSEY, ASSIGNOR TO STANDARD OIL DEVELOP- MENU. COMPANY, A CORPORATION OF DELAWARE CHEMICAL AIPPARA'IUS AND METHOD OF LINING- THE SAME No Drawing.

This invention relates to improvements in the manufacture of apparatus for the distillation of hydrocarbon oils. In accordance with the invention, interior surfaces of stills and the like used inthe refining of petroleum oil are protected by a substantially non-corrodible metallic lining bonded by fusion to the less resistant metal of the still proper.

The improved method is particularly useful for armoring the interior of pressure stills, digesting chambers or soaking drums, and other apparatus of large volume used at high temperature in the commercialrefining of petroleum. By way of example, the meth- 0d will be explained as applied to the soaking drums forming a part of the equipment for cracking oil in the well known tube-and-tank process. In this process oil is heated to .a cracking temperature under high pressure in a coil and discharged into a thermally insulated soaking drum maintained at substantially the same pressure and temperature as the coil. The oil remains for a considerable period in the drum and undergoes further cracking therein.

Soaking drums are ordinarily cylinders about six feet in diameter, and forty feet long. They are made from steel plates varying from two inches to five inches thick, formed by either hot or cold rolling. Butt straps are placed within and without the drum, all the seams are electrically welded, and any rivets that require it are also electrically welded. This welding is ordinarily for tightness only and not for strength. In some cases these cylinders or drums are electrically welded for increased strength, and in others are seamless forgings.

Notwithstanding their massive construction, these drums suffer rather rapid deterioration in some cases. They contain oil at a temperature in excess of 700 F. and at a pressure generally more than 300 lbs. per sq. in. Under these conditions any corrosive impurities in the oil rapidly attack the steel shell. Sulfur, sulfur compounds, and chlorine compounds, are the worst offenders in this respect, and as iswell known are frequently present in petroleum.

By means of the present invention, it is Application flied December 27, 1926. Serial No. 157,425.

practicable to provide an inert lining in soaking drums an thereby avoid to a great extent the expense and danger incident to deterioration of these drums. This method, in a commercially available form, comprises the use of the electric are or a high temperature gas flame to lay down a continuous sheet of relatively inert metal or alloy, simultaneously bonding the sheet by fusion to the metal of the drum shell. Gas flame methods are suitable but generally less economical and satisfactory than the simple electric arcmethod, including the so-called hydrogen welding method. The are method will accordingly be referred to principally herein.

Welding equipment of the kind in present use is generally available for my method. VVeldina practice, however, differs from that followe .in this invention. My method is not welding but what may best be termed fusion-plating.

When lining large cylinders, such as soaking drums, which are to be installed for use in upright position, it is most convenient to place the cylinder on its side. However, the lining may be applied after the cylinder is set in position for use.

Referring particularly to the lining of soaking drums, the workmen enter the drum through one of the large manholes which are provided at each end of the drum. The interior of the drum is first freed of all scale and dirt by sand-blasting, grinding, acid washing or other suitable methods. When a clean metallic surface has been secured.

throughout, the fusion-plating is begun. Hand apparatus may be used, but it is better to provide an electric arc machine mounted the entire wall is plated. The metallic band should be not less than inch thick, for most purposes. The temperature of the arc is so high that the steel of the drum is in a state of incipient melting at the surface in contact with the arc. The added fluid metal bonds with the steel to form What is in effect a unitary metallic body.

While the invention is not restricted to any particular armoring metal or alloy, high chromium steels or irons are generally recommended. For example, the following alloy may be used:

Gr 16-18% Si 1.251.75% G about .10%

The drum is preferably mounted on rollers in a cradle so that it can be turned. In this way it is feasible to work from above while plating the entire cylinder Walls. Difiiculties w1th the gravity flow of the fused metal are avoided in this way for the most part. The interior of the ends of the drum can be plated by starting a metal band at the bottom and building up, or the drum may be up-ended for the plating.

vIrregularities of surface are no obstacle to the practice of the described method, and the butt straps may be covered by the fused metal without difiiculty. In the finished drum there are no points at which corrosion may secure a start. Since welded joints and rivets are especially liable to attack by corrosive bodies in the oil, the plating should be done after the drum has been built, so that all joints may be covered.

The cost of fusion-plating a soaking drum is relatively high, but the expense is justified by the increased service life of the drum. In most cases it is desirable to cover the entire inner surface of distillation and cracking equipment as described, but some of the advantages of the invention may be obtained by plating only the surface which is in contact with oil vapor, or in other cases with liquid oil. The vapor spaceTs usuallymore rapidly corroded than the liquid space, and protection for the former is particularly desirable. v

I claim:

In the manufacture of steel distillation and cracking equipment, the improvement which comprises fusing a chromium-iron alloy and depositing it upon the inner surface of said equipment at a temperature suflicient to cause the alloy to bond with the steel.

In testimony that I claim the foregoing as my invention, I affix my signature.

RALPH L. DUFF.

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